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Finished Canopy Hinge Blocks and More – 7 hrs

April 8, 2012 Leave a comment

Sunday Apr 8, 2012

This has been an unusual week. We had relatives in town from Wednesday evening through Saturday night so my work on this project was in little short sessions whenever it was convenient. So this post summarizes all the things I did since Monday April 2.

Tuesday Apr 3

On Tuesday I worked on the C-710 pushrod for the canopy release side handle. The rod must be cut to length, drilled out with a #3 bit and tapped to 1/4-28 on each end. The plans say to cut the length to fit at assembly but there is an overall length provided on the drawing so I cut it a little longer than the drawing. I can trim it a bit later if necessary. As shown below, I drilled the ends and tapped them for the rod ends.

Wednesday Apr 4

On Wednesday I started working on the links of the canopy release. These are a royal pain in the behind because they are steel and you have to drill holes on the ends for cotter pins and slot them for the release pins and release shaft. I drilled the cross holes with my drill press. I marked the locations and drilled with a #40 bit,then enlarged to #30, then #12. You have to be careful to make sure the two holes are parallel.

Here is a shot of the short link with the cross holes drilled.

Then came the trickier part which was cutting the slots. I used a reinforced cutting wheel on my dremel tool for the basic cut. The wheel is about .050 thick and the desired slot width was .060 so this required a steady hand. The first one took a while to cut as I did it very slowly. I finished the slot with a tiny file. More on this later.

Thursday Apr 5

Thursday night I had a little bit of time so I made the spacers for the elevator pushrod where it attaches to the elevator horns. You can see them installed in this shot.

I also took the vertical stabilizer off so I could prime the shims and parts that connect it to the fuselage.

I received the new C-617 UHMW bearing block in the mail today from Vans. The photo below shows the old scrap block beside the new block. It did not take long to transfer drill the two #10 holes from the scrap block. You can bet I was careful to not allow the drill bit to chew up the block the way I did last time. On the drill press I now apply smooth downward pressure while drilling through then shut off the drill before trying to back the drill out. That seems to work pretty well.

Saturday Apr 7

On Saturday I had the chance to finish installing the new C-617 block on the forward fuselage and drill the 1/4 inch hole for the canopy latch pin.

Because I have read much about the trials of fitting the canopy frame I decided to rivet the canopy frame skin onto the weldment and perform and check of the fit with the forward skin. The photo below shows what that looked like.

As expected I found that the skins would not meet leaving a gap of about 0.100 inch as you can see below. It looks like the shims between the C-617 and C-618 blocks is preventing the canopy frame from sliding forward any farther. Not surprising. So I will have to trim about .070 to .080 off those shims to get to the final position. The seal strips are also pretty close so I may need to trim those a bit also.

Sunday Apr 8

Back to work on the canopy release mechanism. I finished slotting the short link. It is 1/8 inch wide on the left for the hinge pin (bolt) and .060 on the right for the crank. Here I assembled the short link to see if it moved smoothly. It did after a little work with the jeweler’s file.

The rest of the time today was spent preparing and priming a batch of parts including the angle and plates for mounting the vertical stabilizer and parts of the canopy release mechanisms. I also primed and painted the F-704K upright cap strips.

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Roll Bar Installed for Good – 2 hrs

April 1, 2012 Leave a comment

Sunday Apr 1, 2012

This afternoon Scott came over again and helped me rivet the F-705 bulkhead to the longerons and the F-705C angle on the right side of the fuselage. That gets everything in this area locked down so I can fit the canopy latch bar which mounts in this area. With that completed I remounted the roll bar and torqued the nuts and bolts so this is on for final (I think).

These bolts are a little difficult to get tools on to torque them. But I lucked out and had the right combination of tools to get it done.

Then I made the C-620 bearing block with the two relief notches on the top and two holes through the sides. I cut the notches on the band saw. It’s amazing how tough this material is. And I drilled the holes very carefully. I don’t want to mess up another UHMW block.

Started Canopy Hinge Blocks – 5 hrs

March 31, 2012 Leave a comment

Saturday Mar 31, 2012

Today I officially started working on the finishing kit. The first step in this kit for the tip-up canopy design is installing the canopy hinge blocks. They are ultra high molecular weight (UHMW) plastic blocks that provide low friction and good wear resistance. You start by marking the location for two holes from the drawing and drilling the first hole using a #10 bit. Here is a photo of one of the C-617 blocks.

Then I installed the block onto the F745 rib of the forward rib structure using an AN3 bolt though the pre-drilled hole in the rib and the hole I just drilled in the block. With the top edge of the block aligned to the rib I clamped that in place and drilled through the block usingĀ  the second pre-drilled hole in the rib as a guide.

Then I clamped the block to the thinner C-618 blocks and match drilled through to make a matched set.

Then I drilled another hole in the C-617 blocks using the second hole center I marked in the first step above. That is when things went bad. The first C-617 turned out fine. The second block was going well as I drilled down through the block on the drill press but as the drill bit was being extracted the bit grabbed the block and twisted it leaving the hole a useless oval shape seen below on the upper left hole. This is disappointing because now I have to order a replacement C-617 block and that will take a week.

I went on and made the C-618 shims from 1/4 inch aluminum bar. I don’t know why but Vans gives you about 4 times more material than you need for these.

One hole was drilled through the C-618 shims based on measured dimensions. Then the shim was mounted to the C-617 block and the second hole was match drilled using the second hole in the C-617 as a guide. I could only do one of these because of the botched C-617.

Then I inserted the C-617/618/619 assembly between F-644 and F-745 ribs in the forward section of the fuselage and slipped bolts through the holes until they contacted the face of the F-644 rib. I clamped the ribs and blocks together using just enough pressure to hold the clamp in place. Next I clecoed the F-771 front top skin in place to maintain the proper position of the F-644 ribs. I did not cleco the portion of skin that is outboard of the F-745 ribs so the skin could be lifted to provide access for drilling. Then I removed one bolt from the assembly and drilled the F-644 through the hole, reinserted the bolt all the way through F-644 this time, and continued remove the second bolt and drill through the F-644 again. The 1/4 inch hole was not accessible so I removed the sub-panel center section, clamped the bearing parts to the F-644 rib and drilled the 1/4 inch hole using the C-617 as a guide.

Then I put it back together to see how it looked. Not bad.

Since a can’t finish the other bearing set now I started looking at the rear latch bar installation instructions. This will be coming up next but I realized that I need to rivet the F-705 bulkhead to the longerons before I can accurately align this so I decided to do that next. My friend Scott was helping me so we began on the left side and got most of that finished.